Piston



(No Model.)

' Y J. G. HALE.

PISTON. No. 254,960. PatentedMar. 14,1882.

q WITNESSES ATTORNEYS.

UNITED STATES PATENT OFFICE.

JOHN o. HALE, on s'rEPHENs CITY, VIRGINIA.

PISTON.

SPECIFICATION forming part of Letters Patent No. 254,960, dated March 14, 1882, Application filed October 4, 1881. (No model.)

To all whom it may concern Be it known that I, JOHN CARTER HALE, of Stephens City, in the county ot' Frederick and State ot" Virginia, have invented a new and useful Improvement in Pistons, of which the following is a full, clear, and exact de scription, reference being had to the annexed drawings, forming part ofthis specification.

The object of my invention is an improvement in the class of pistons which are formed of two disks or heads inclosing a vacant space between them, in which a valve or valves are arranged to automatically open and close passages leading into said space.

The improvement is embodied in the coustruction and combination of parts hereinafter described and claimed.

In the accompanying drawings, Figure l is a vertical section of a cylinder and piston, showing my improvement. Fig. 2 is an end View ot' the piston and packing, one oi"V the heads ofthe piston being removed; and Fig. 3 is a side elevation of the piston,showing the joint in the packing.

The piston A is composed of two cast-iron heads, a a', of equal size, having a peripheral recess, b, formed in a lateral annular rim, c, near the circumference, and adapted to be titted together, so as to make a steam-tightjoint between the two rims. A lug, d, in one ot' the rims ts into a corresponding-recess in the other rim, and at a point opposite thereto the rims are curved inward, to form the ball-cage c, which is provided with a ball, j', and ports g and h, leading through the piston-heads, respectively, and a third port, j, leading through the rims e at the pointofjuncture. Agroove, i, is formed near the edges ofthe rims c, so as to form acontinuous channel in thebottoin of the recess b, when the heads are secured together. With this construction ahollow closed space is formed in the piston, rendering it lighter than a solid pistonwithout sacrificing any essential element of strength. The steam-paeking 7a consists of a single band or 1ing,which is cut at a given point, and has its two ends recessed on opposite sides, so as to allow the ends to overlap each other laterally. To make the joint thus formed steam-tight,a lining, l, is secured to the inner surface ot' one ot' the ends, so as to project beyond the joint, and to counteract the effects of increased thickness at this point the band is made correspondingly thick at the opposite side. y

It is designed that the packing 7c shall not act as a spring, but shall be expanded solely by the action ofthe steam. The packing thus piston a portion of it will enter through one of the ports g la into the cage e, and thence through the port j into the groove c', until the packing k is expanded against the walls ofthe pistonchamber. The expansion ofthe packing will thus vary according to the amount ot' steampressure exerted, and the packing Will always relieve itselt' of strain as soon as the steam is shutott'. With this construction the piston will consist ot' only four simple parts, which may be easily detached from eachother and put together again perfectly by almost any one, since the packing is self-adjustable, and owing to the lightness ot' the piston and the equal distribution of friction the expense of boring out worn cylinders will in great measure be obviated. It it designed that the ball and packing shall be made ofthe best refined soft brass, and the seat and joints ground to make them steam-tight.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is A The combination ot' the heads a a', having a liollowspace inclosed between them, a recess, b, formed iu their adjacent perlphei'iesi,al1d provided with a groove, ,in its bottom, a ballcage, e, communicating with the said recess and groove through the port j, and with opposite ends of the cylinder through ports g and h, the ballf, andthe packingk, having its ends recessed and overlapped laterally, and provided with a lining, Z, secured to one end and underlying the said joint, substantially as shown and described,and for the purposes set forth.

JOHN CARTER HALE. Witnesses:

JAMES A. HUDSON, J EREMIAH S. OLEvENd-ER.`

IOO 

